Metro-style apps are very similar to Windows Phone apps. They have a similar application model (for example they can be suspended, and when suspended they can be killed by the operating system if memory is needed), so they need to maintain state. Also, and that is the topic of this post, they cannot be ended by the user in a “normal” way, i.e. there is no File / Exit menu and no “X” button in the corner. Once started, the application remains in memory until the following happens: